Human Factors f berengueres sweb654_2021_sp

1. HUMAN FACTORS
HCI & USABILITY
MARCH 3 2021
SWEB654 2021 SP UAEU jose berengueres

2. Contents
• Etymology
• Domains of specialization
• History of the field
• Human factors organizations
• Methods
• Monkeys & Memory game

3. Etymology
• application of psychological and physiological principles to
the engineering and design of products, processes, and
systems, includingApps

4. Goal(s)
• goal of human factors is to reduce
– human error,
– increase productivity, and
– enhance safety

5. Domains of
specialization
• The field is a combination of numerous disciplines, such
as psychology, sociology, engineering, biomechanics, indu
strial design, physiology, anthropometry, interaction
design, visual design, user experience, and user interface
design.

6. Domains of
specialization
• "human factors" =
"ergonomics"

7. Intl orgs
• The International ErgonomicsAssociation defines
ergonomics or human factors as follows:[5]
• Ergonomics (or human factors) is the scientific discipline
concerned with the understanding of interactions among
humans and other elements of a system, and the
profession that applies theory, principles, data and
methods to design to optimize human well-being and
overall system performance.

8. Applications
• occupational health and safety and productivity.
• prevent repetitive strain injuries and
• other musculoskeletal disorders
• FH = "fit" between the user, equipment, and environment
or "fitting a job to a person”
• Becuase users not superman, limited cognitive abilities
– 7 chunk memori limit
– Hicks law

9. Hicks Law
• increasing the
number of choices
will increase the
decision
time logarithmically

10. Hicks Law
• Hick’s Law
• (1) H = log2(n + 1).
(2) H = Σ pi log2(1/pi + 1).
• H = the information-theoretic entropy of a decision.
n = the number of equally probable alternatives.
pi = the probability of alternative i for n alternatives of unequal
probability.
• The time it takes to make a decision is roughly proportional to H, the
entropy of the decision (the log of the number of alternatives), i.e.T = k
H, where k ~ 150 msec.
• This can be used to make a time estimate for how long people will take
to make a decision in using a user interface, such as choosing a menu
item, choosing a tool, or selecting an item on a navigation bar. Cognitive
modeling approaches such as GOMS apply this to making predictions of
human performance.

11. Fits Law • 1954 paper by Paul Morris Fitts proposed a metric to
quantify the difficulty of a target selection task.

12. FITS LAW
https://www.youtube.com/watch?v=E3gS9
tjACwU&ab_channel=Computerphile

14. History of
the field
• What is more expensive a pilot or a jet?
• WWII expensive pilots
• Fitts and Jones (1947), who studied the most effective
configuration of control knobs to be used in aircraft
cockpits.

15. Methods
• Ethnographic analysis
• Focus Groups
• Iterative design:
• Meta-analysis:
• Subjects-in-tandem
• Surveys and questionnaires
• Task analysis
• Human performance modeling:
• Think aloud protocol
• User analysis

16. Methods
• Kansei method
• "Wizard of Oz
• "Wizard of Oz
• Time studies
• Work sampling

17. Appendix • MUSCLE memory (Monkey Cambridge brain science)
• CHESS SYMBOL CHAGE CASE